In what could be the first spillover from France’s intervention in Mali, Islamist militants attacked and occupied a natural gas complex partly operated by energy company BP in southern Algeria on Wednesday.

Two foreigners were killed and possibly dozens of others, including Americans, were taken hostage.A militant group claimed responsibility for the attack, saying it was in revenge for Algeria’s support of France’s operation against al-Qaida-linked Malian rebels groups far to the southeast. It said it was holding 41 foreigners, including seven Americans.